Railway traffic controlling apparatus



Nov. 19, 1946. T. PAsoE ET AL 2,43 i587 RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Dec. 8, 1944 Patented Nov. 19, 1946 UNITED RAILWAY TRAFFIC CONTROLLING APPARATUS Frank T. Pascoe, Carnegie, and Arthur L. Jerome, Edgewood, Pa., assignors to The Union Switch & Signal Company, Swssvale, Pa., a corporation of Pennsylvania Application December 8, 1944, Serial No. 567,188

Our invention relates to railway tral'lic controlling apparatus and particularly to improved circuits for use in centralized traic control machines for remote control of traiiic in track stretches in which traic may move in either direction.

In Figpl of application for Letters Patent of the United States, Serial No. 501,254 of H. S. Young, filed September 4, 1943, there are shown interlocked circuits at the control oice governed by the signal control levers which govern train movements into the opposite ends of a track stretch, so as to prevent interference with train movements in the event ot improper manipulation of these levers and to prevent the reversal of the direction of trallic except when the single track stretch is unoccupied and the signals governing entrance oi traic into the stretch ane at stop.

An object of our invention is to provide an improved system of the type described which upon operation of the office equipment to permit a change in the direction of traiiic promptly cancels the existing block indications.

A further object of our invention is to provide an improved system of the type described which upon operation of the oiice equipment to permit a change in the direction of traino prevents response of selected indication relays to indication codes until control codes have been sent to both ends of the stretch to condition the equipment in the neld to establish traflic in the direction determined by the oflice equipment.`

Another object of our inventioriis to provide an improved system of the type described which upon operation of the oiiicel equipment to permit a `change'in the direction oi traic promptly establishes circuits for the starting relays governing transmission of control codes to opposite ends of the lstretch t'oiihsure` that control codes will be transmitted to both ends oi the stretch to thereby make `certain that the wayside apparatus will prepare the stretch for traffic in the direction determined by the oice equipment.

A furtherA object ofthe invention is to provide an improved system of the type described which operates to maintain the circuits for the start ing relays until the wayside apparatus prepares' the stretch for traffic in the direction designated by the oce equipment and to `thereupon interrupt these circuits for the starting relays.

Another object of the invention is to' provide improved apparatus ofthe type described for use where there is an electrically locked switch at an intermediate pointA in a track stretch.

17 Claims.

A further object of the invention is t'o provide apparatus of the type described which operates to prevent improper changes in the designated trafc direction following movement of the switch lock lever.

Another object of the invention is to provide improved apparatus of the type described which is arranged so that the operators control of the traffic direction relay for; a track stretch is4 certain to be terminated after occupancy of the stretch even though the stretch becomes occupied beiore block` clear indication codes have been sent to the central oce. Y

Other objects of the invention and features of novelty will be apparentfrom the following description taken in connection with the accompanying drawing;

We shall describe one form of railway traffic controllingl apparatus embodying our invention, together with a modication thereof which We may employ, and shall then point out the novel features thereof in claims.

In practicing our inventionwe provide a master directional relay of the polar stick type for designating the direction oi traii'lc in each track stretchand provide circuits governed by the levers controlling the signals at the entrance ends of the stretch for operating the relay contacts to one position or the other providing the stretch is vacant andthe signals are at stop. Contacts oi this directional relay control the polarity of the' energysupplied to a neutral auxiliary stick relay so that this relay always releases on movement of the contacts of the directional relay. The auxiliaryl relay when released energizes the block indication relays to cancel the existing indications and prevent registration of new indications, while the auxiliary relay when released VenergiZes a block repeater stick relay which establishes circuits for the starting relays to insure transmission of control codes to both ends `oi the stretch and also provides a circuit for the directional relay to permit the relay to be operated pending establishment of traiiic in the stretch. The auxiliary relay, when released, is picked up upon energization of the starting relays for b oth ends of the stretch. The stick circuit for the block repeater relay is interrupted on receipt of indica--Y tioncodes from the field stations showing that thewayside apparatus has established traffic in the designated direction or on receipt of an indication code showing that a detector sectionV is occupied, thus showing that atrain has entered theV stretch. The switch lock` lever governs the 3 block repeater relay and the block indication relays to insure proper operation of the equipment on movementl of this lever.

In the drawing,

Fig. 1 shows a portion of a suitable machine located at a control oiiice and including control panels for two iield stations located at opposite ends of a single track block, as indicated by the miniature track diagram at the top of the view, and

Figs. 2 and 3 are fragmentary views showing modifications which we may employ.

Similar reference characters refer to similar parts in each of the three views.

In most instances in the drawing the relay contacts are located directly under the winding of the associated relay, but in some cases, in order to simplify the drawing, relay contacts are separated from the relay winding and in these instances the relay withwhich the contacts are associated is designated by appropriate reference characters placed above the contacts.

The office and the field stations are each provided with a suitable source of direct current, such as a storage battery, not shown, the terminals of lwhich are designated B and C in the drawing.

.Referring to the drawing, there is shown in the upper portion of Fig. 1 a diagram of a stretch of single track railway between two passing sidings together with'certain of the eldcircuits employed inl connection with this invention, while the lower portion of this figure shows a portion of a suitable machinelocated at the control oflice and incorporating this invention;

In the drawing diagrammatic connections are shown between relays at the field stations and indication relays in the oice but it should be understood that communication between the eld stations and the oiiice is established by a code system which may be of thetype shown in Letters Patent of the United States No. 2,229,249, issued January 21, 1941, to L. V. Lewis, or in application for Letters Patent of theUnited States, Serial No. 496,907, led July 31, 1943, by A. P. Jackel, and described in Manual 506A of The Union Switch and Signal Company, Swissvale, Pa.

Consideration of the detailed mode of operation of the code communication Asystem is not needed for an understanding of our invention and it is deemed suflicient to point out that a eld station is provided at each end of each track stretch to be controlled and that coding units are provided at the office and at each field station and are connected by a pair of line wires, not shown, over which control codes are transmitted at-.times from the ofiice to a selected field station, while at other times indication codes are transmitted over the same line wires from the different iield stations to the ofce without interference, and that the transmission of each code includes the temporary establishment of a plurality of communication channels, as for example, seven, between the oflice and a station to position a group of relays.

Each code includes a distinctive code call by means of which a'selector relay I-2S or 3-S at the oice and a similar relay, not shown, at one station onlyis energized to eifect temporary establishment of seven communication channels between the oflice and the station. The diierent stations havediierent code calls, consequently the selector relays for different stations or panels are'not energized at the same time, and the samey the channels employed in the transmission of indication codes are designated III, I2, it, I4 and l5, the numbers employed to designate -these lchannels being the same as are employed to designate the' corresponding channels in the above-identified application of H. S. Young.

, It is to be understood that the system of our invention is made up of a number of unit portions generally similar to the one shown in the drawing, but, as the invention may be fully understood from one such portion, only one has been illustrated'in the drawing.

The equipment at each eld station includes a starting relay, not shown, which responds to a change in position of any of the associated indicating relays to provide connection from terminal B of a source of current to the indication channels to effect delivery of indication codes over the 'line wires during the time that a delivery relay D at the ofiice is energized to thereby position a group of indication relays in acco-rdance with the conditioncf energization of the indication channels.

The indication relays at the ofce governed from the field station at the left-hand or west end of the single track stretch include a relay ITK which ,controls a lamp in the track diagram of the control machine tc indicate the condition of section IT- containing the track switch IW, the relay ITK being controlled by the track relay I'IR for the track section; a signal indication relay `ZRILIK governed by relay ZRRGP which repeats the stop indications of the signalsV ZRA and ZRB; and a block indication relay ZRBK controlled by the relay ZRBR which in turn is governed by traffic conditions in the single track stretch. The control of the relays ZRBR and llLBR. is shown dia-` grammatically in the drawing, but these relays may be governed through the wayside signal system, as explained in the above-identified application of H. S. Young, so as to indicate that the block is clear only when the wayside signal apparatus conditions the stretch for traific in one direction or the other.

The relays at the field station at the righthand end of the singletrack stretch function in a similar manner to control indication relays STK, 4LBK and GLHK at the oice.

'Ir'he block indicationr lamp BKE in the-track diagram of the control machine is governed by the relays ZRBK and fiLBK, one of which indicates the condition of a portion of the single track block and the other that of the remainder.

The signal levers ZSIG and 4SIG are the usual levers forV the code control of the signal stick relays, not shown, at the field stations at the opposite ends of the single track stretch. The signal levers ZSIG and 4SIG are electrically interlocked with respect to the control of train movements into the intervening single track stretch by the master directional polarizedrelay 24LP, as in the above-identifiedapplication of H, S. Young and also in his Letters Patent of the United States No. 2,326,991. Y

The push buttons I'-2STB anda-:1STE are the starting buttons for operating the usual code starting relays l--2ST and S--IiST by means of which control codes are .initiated and the corresponding stations selected. Each starting relay when energized initiates a control code as descriloed in Patent No. 2,229,249 including a code call for energizing a selector relay S for the same panel. Each selector Vrelay when energizedV releases the associated starting relay and connects terminal B of a local source of energy to selected ones of the control channels in accordance With the positions. of the signal levers and of the contacts of the master directional relay 2--4LP, and at the selected station relays are operated in accordance with the condition of energizaticn of each of the control channels.

The equipment is arranged so that when energy is applied to channel 2 and a control code is transmitted to a field station, a traflic directional ccntrol relay FS, not shown, is operated to condition the wayside apparatus to make the end of the stretch at which this relay is located an exit or leaving end. Similarly, the equipment is arranged so that, when energy is not applied to channel 2 and a control code is transmitted to a iield station, the traffic direction control relay FS, not shown, is operated to condition the Wayside apparatus to make the end of the stretch at which this relay is located an entrance end so that the signal at this point may be controlled by the Wayside circuits on operation of an associated code controlled signal relay, not shown.

The equipment is also arranged so that, when energy is supplied to the code channel governing a signal control relay as, for example,l channel 5 or l, and a control code is transmitted to a held station, the signal control relay at that station is operated to render the signal subject to the control of the wayside circuits. When energy is not supplied to the code channel governing a signal control relay, and a control code is transmitted to a eld station, the signal control relay at that station is operated to keep the signal at stop irrespective of the Wayside circuits.

The equipment at the. left-hand or West end of the stretch includes a relay controlled over channel ll and operating as explained in the above-identiied application of H. S. Young to at times condition this end of the stretch to be an exit end and to prevent transmission of a block clear indication code by the field station at this location,

The equipment is shown in the condition which it assumes when the track stretch is vacant, the signals 2R and 5L are at stop, and the Voffice equipment conditions the stretch for Westbound trahie. As the stretch is vacant, the block indication relays QRBK and LBK and the detector section indication relays ITK and STK are released and the panel lamps BKE, ITKE and ETKE are extinguished. As the signals 2R and iL are at stop, the relays ERHK and @LI-IK are released, While the Westbound direction indicator lamp WFE is lighted by energy supplied over normal polar contact 2S of relay .2i- 4LP and back contact 2i of relay Z-BKSR. As the block detector section and signal indication relays are all released, energy may be supplied over the circuit controlled by` these relays toV the relay 2 flLP, but as the signal levers 2 and 4 are both in their center positions the circuits for supplying energy to the relay 2-4LP are interrupted.

It is assumed that the traffic direction relays, notA shown, at the field stations were previously 6 operated to condition the Wayside apparatus for Westbound traffic.

At this time the relay Z-llBKSR is released, while relay 2-4LPS is energized by current supplied over its stick circuit including its own contacts 23 and 2d, normal contact 25 of relay 2 4LP, Winding of relay 2-5LPS from left to right, and normal polar contact 26 of relay 2-4LP, and the contacts of relay Z-LSLPS are picked up and do not establish circuits for the relays ERBK, iLBK and 2-4BKSR.

If it is desired to clear one of the signals 4L, the lever QSIG is moved to its lefthand position and the starting button S--ASTB is pressed to establish a pick-up circuit for the starting relay S-QST and it picks up to establish a stick circuit for itself and to initiate operation of the cnice coding unit to transmit a control code to the field station at the right-hand end of the stretch. At the time the starting button 3-4STB is depressed, its contact 23 is closed but as relay E-BKSR .is released its contact 29 interrupts the circuit for supplying energy to relay l--ZST and it remains released and does not cause a control code to be sent to the field station at the left-hand or West end of the stretch.

The control code transmitted as a result of picking upy of relay 3-4ST causes a selector relay S-S to pick up with the result that terminal B of the battery is connected over normal polar contact 3E! of relay 2-4LP, front contact 3l oi relay i5-3S and left-hand contact 321 of the lever ISIG to channel 5 and a control code is transmitted to operate a signal control relay, not shown, and places one of the signals 4L under the control of the Wayside circuits, the one of the signals being determined by theposition of switch 3W in the Well-known manner.

When selector relay -QS picks up, its fro-nt contact 2l is closed but as contact 35i of relay 2-lLP is in its normal position, the battery is not connected to channel 2 and the control code sent to the field station at the right-hand end of the stretch causes the trailic direction relay at that location to maintain that end of the stretch as an entrance end.

When one of the signals l. displays a permissive indication, relay.1 dLRGP releases so that energy is supplied to channel it and when this eld station sends an indicationV code to the oice the relay iLHK is picked up and is held by its stick circuit, while on picking up of relay ALHK its contact 33 interrupts the circuits for energizing relay 2-llLP and thus prevents movement of the contacts of this relay to change the designated trahie direction While one of the signals 4L authoriaes entrance of traic into the stretch.

Ii' a train accepts the signal and entersthe stretch, the Wayside equipment operates in the usual manner so that the signal is put to stop and an indication is sent to the ohce to release relay @LI-IK, While the track and block relays control the indication codes sent to the oice to pick up the block and detector section relays to light the lamps BTKE, BKE and iTKE in the track model, and to interrupt the circuits of the relay E-IILP to prevent a change in the designated traiic direction during occupancy of the stretch. When the stretch is vacated and the sig nals are at stop, the indication relays are released and extinguish the lamps STKE, BKE and iTKE and establish the vcircuits of the relay 2-4LP.

When the stretch is vacant and the signals are at stop, the operator may change the designated or BTK pick up.

trafc directionby moving the levers ZSIG and ASIG to supply energy to relay 2-4LP. To change the designated traino direction from westbound to eastbound, the lever 4SIG must be in either its center or its right-hand position and the lever 2SIG is moved to its right-hand position. If at this timethe switch lock lever ZWL is in its center position, as shown, energy is supplied over back contact 33 of relay dLHK, back contact 34 of relay Rl-IK, back contact 35 of relay 4LBK, back contact 36 of relay ZRBK, back contact 31 of relay STK, back contact 38 of relay l'IKycontacts 46 and 4| of lever ZWL, contact I42 of lever 2SIG in its right-hand position, and contact 43 of lever 4SIG in its right-hand or its center position to the upper winding of relay 2-4LP. The energy supplied to this winding moves the relay contacts from their normal to their reverse position so that contact 26 interrupts the circuit of lamp WFE and establishes the circuit to permit energy to be supplied to lamp EFE. A

On movement of the contacts and 26 of relay Z-fiLP to their reverse position, there is :a reversal in the direction oi flow of energy 'through the winding of relay 2-4LPS and the contacts of this relay release with the result that contact 23 interrupts the relay stick circuit and the relay contacts remain released. On release of relay 2 LPS itscontacts 45 and 46 establish circuits for the relays RBK and @LBK and their contacts pick up While contact 47 Vof relay 2-4LPS establishes the pick-up circuit for relay 2-4BKSR, this circuit including contact i8 of lever 2WL which is closed only in the center position of this lever. When relay Z-ISBKSR picks up, its contact 49 establishes a stick circuit to keep the relay energized until relays ERBK and LBK both release, or one of the relays ITK In addition, when relay 2-4BKSR picks up, its contact 2i interrupts the circuits controlled by contact 2li of relay 2-4LP for` lighting the lamps WFE and EFE, thus preventing lighting of either of these lamps until establishment of the new direction of traflic is completed. When either of the relays ZRBK and 4LBK is picked up, energy is supplied to the lamp BKE and it is lighted. Lighting of lamp BKE at a time when lampsY WFE and EFE are both dark provides a distinctive indication of the fact that a change in the designated traffic direction is in process.

In addi-tion, on picking up of relay 2-4BKS`R its contact 29 establishes the circuit controlled by starting button 3-4STB for energizing relay l'-2ST and contact 50 of relay 2-4BKSR establishes a circuit controlled by starting buttonVl-ESTB for energizing relay 3-4ST. Accordingly, after picking up of relay 2--4BKSR energy is supplied to the starting relays for the control panels for both ends of the stretch when the starting button for the panel for either end of the stretch is depressed. As pointed out above, on movement of the contacts of relay 2-4LP there is a reversal in the polarity of the energy supplied to relay 2-4LPS and its contacts re lease promptly While the relay 2-4BKSR picks up immediately upon release of relay Z-LELPS, with the result that the contacts of relay 2-4BKSR are picked up and establish the circuits for the starting relays before the operator can move his hand from a signal lever toa starting button. Consequently, when a starting button is depressed following a change in the designated traihc direction, the starting relays for both ends of the stretch are certain to be energized and control codes are certain to be transmitted to both ends of the stretch and the wayside equipment is certain to be conditioned for the new direction of traiic.

When relays ZRBK and 4LBK pick up, .their contacts 36 land 35 interrupt the circuits for operating relay Z-rlLP, but at this time front contact 39 of relay 2-4BKSR is closed and shunts the contacts 36 and 35 of relays 2RBK and 4LBK to thereby enable the relay 24LP to be operated to restore the original tranic direction if this is desired.

When the starting relays l-ZST and 3-4ST are picked up, the oiiice coding unit is caused to transmit control codes to the neld stations at the opposite ends of the stretch, While as soon as the oiiice coding unit starts to transmit a control code, energy is supplied to terminal 51, as explained in the above-identied application ol A. P. Jackel, With the result that energy is supplied from this terminal over front contact 52 of relay 3-4ST, front contact 53 of relay I-ZST, front contact 54 of relay 2-4BKSR, front contact 55 of relay ZRBK, front contact 56 of relay 4LBK, contacts 58 and 24 of relay 2-4LPS, reverse polar contact 25 of relay 2-4LP, winding of relay 2-4LPS, and reverse polar contact 26 of relay 2-4LP to terminal C. The energy supplied over this circuit to relay 2-4LPS picks up the relay contacts with the result that contacts 23 and 24 establish for the relay a stick circuit governed by contacts 25 and 26 of relay 2-4LP so that energy of the same polarity is supplied to relay 2--4LPS over its stick circuit as Was supplied to the relay over its pick-up circuit. In addition on picking up of the contacts of relay 2-4LPS contact v2l! is disengaged from contact 58 so that the .pick-up circuit for relay 2-4LPS is interrupted.

When relay 2-4LPS picks up. its contacts 45 and 46 interrupt the circuits which they control for energizing the relays ZRBK and 4LBK, but these relays are maintained energized by current supplied over their stick circuits until indication codes are received from `the field stations, so the lamp BKE remains lighted. In addition, when relay Z-llLPS picks up, its contact 4l interrupts the pick-up circuit for relay 2-4BKSR, but this relay is maintained picked up by energy supplied over its stick circuit which includes back contact 92 of relay IIK, back contact S3 of relay STK, its own front contact 49, and front contacts 60 and 6I of relays ZRBK and 4LBK, and contact 2| of relay 2-4BKSR continues -to interrupt the circuits o-f lamps WFE and EFE, While contacts 29 and 5U maintain the circuits for the starting relays so that depression of either starting lbutton energizes both starting relays.

When the office coding unit operates to transmit a control code to the eld station at the lefthand end of the stretch, front contact 64 of relay |-2S is closed, but as contact 30 of relay 2-4LP is now in its reverse position, energy is not supplied to channel 2 and the control code sent to .the eld station at the West end of the stretch causes the traic direction relay at that location to change that end of the stretch from an exit to an entrance end. A

At .this time energy is supplied over reverse polar contact 30 of relay 2-4LP, front contact of relay I-ZS, and right-hand contact 65 of lever 2SIG to channel 'l so the control code transmitted to the eld station at the left-hand end of the stretch operates the signal control relay antena @i at that location to permit' clearing of signal 2RA or ZRB.

When the oce coding unit operates to transmit a control code to the eld station at the righthand end of the stretch, the relay 3-4S is picked up and energy is supplied over reverse polar contact 30 of relay Z-ALP, and front contact 2l of relay 3-S ta channel 2 so that the traflic direction relay at the east end oi the stretch is operated to change that end of the stretch from Ian entrance to an exit end. At this time, front contact 3l of relay 3-4S is closed but as contact 30 of relay 2-4LP is in its reverse position, energy cannot be supplied to channel 5 and .the control code sent at this time causes the signal control relay at this eld station to maintain the signals LA and ALB at stop As a result of transmission of control codes, .the starting relays l-ZST and 3--4ST are released in the usual manner, and ltheir contacts 53 and 52 interrupt the pick-up circuit for relay 2--4LPS- 'Ihe control codes. sent to the field stations cause the Wayside equipment to prepare the stretch for eastbound traino While one of the signals 2R clears and causes relay .lRRGP to release. When the Wayside equipment operates to establish eastbound traic indication codes `are sent to the oice .to release relays ZRBK and LBK, While release of relay ZRRGP causes an indication code to be sent to the oice to pick up relay ZRHK.

On release of relays ZRBK and ALI-,IK their contacts 60 and VIiI interrupt the stick circuit for relay Z-ABKSR and it releases to additionally interrupt its own stick circuit .and its contacts starting buttons for the starting relays at opposite ends of the stretch, while contact 2| of relay Z-dBKSR establishes the circuit including reverse polar contact of relay 2-4LP to light the lamp EFE to indicate that eastbound traic has been established. On release of relays ZRBK and 4LBK the circuits of lamp BKE are interrupted and this `lamp is extinguished.

When relay Z-ABKSR reelases, its contact 39 in the circuits of relay 2-4LP is openedand control `of `the relay 2-4LP is restored to the relays ZRBK and llLBK. At this time, relay .ZRT-IK is picked up and its contact 34 interrupts the circuits of relay 2-4LP to thereby prevent operation of this relay to change the designated traiiic direction. 4In addition, on release of relays ,l 2-4BKSR, ZRBK and ALBK their contacts .54, 55 and 56 interrupt the pick-up circuit of relay If an eastbound train now accepts the signal ,2R and enters the single track stretch, the signal 42R, is put to stop and the track relays of the cccupied sections are released and control codes are sent to the oilice to release relay ZRHK and to pick up relay ITK so that contact 38v of relay ITK interrupts the circuits of relay 2-4LP `to prevent a change in the designated traic direc,- tion during occupancy of the stretch. As the train advances through the stretch, control codes are sent to the office to pick up relay ERBK so that its contact 36 interrupts the circuits of relay .2-4LP to prevent a change in the designated traic direction, While a contact of relay ZRBK establishes a circuit for the lamp BKE. Lighting of this lamp accompanied by lighting of lamp EFE provides a distinctive indication of occupancy of the stretch. On continued movement of the train through the stretch, the block and detector section indication relays operate in the er 29 and 5 9 interrupt the circuits governed by the l0 usual manner to control the circuits of the lamps inthe "track model` on tha-panel `of the control machine, While contacts vof these relays interrupt the circuits of the relay Z-liLP to insure that the contacts o f this relay remain in their right-hand position and maintain eastbound trafc.

Because of code congestionon the C. T. C. system codeline, indication codes from the field stations to the ofce may be delayed and the eastbound train maylenter the stretch before indication codes have .been sent to the oiiice t0 release relays ZRBK and IILBK, and under these conditions indication codes subsequently sent to the oilice cause relay ZRBK to remain picked up to maintain `the stick circuit for relay 2-4BKSR. If relay Z-llBKSR remains picked up, its contact 39 maintains the connection shunting contacts and 36 of relays 4LBK `and ZRBK in the circuits of relay 2-4LP, thereby permitting lthe operator to disestablish the designated traflic direction with resultant interference with progress o f the train present in the stretch. This system is arranged so that contacts of relays I TK and 3'IK are included in the stick circuit of relay yZ-,IlBlfSlt and on entrance of an eastbound train into the stretch, an indication code is certain to be transmitted to the oiice to pick up relay ITK with the result that its contact 92 interrupts the stick circuit -for relay E-BKSR and causes it to release if it is not already released. Accordingly, if a train enters the stretch before the block clear indication codes are transmitted to the oice to release relay Z-QBKSYR this relay will be released when an indication code is sent to the office reporting occupancy of a detector section, and as relay 2-4BKSR is certain to be released after entrance of a train into the stretch, its Vcontact 39 is certain to interrupt the connection shunting contacts 35 and 36 of relays ALBK vand ERBK in the circuits of relay 2-4LP and thereby prevent the operator from disturbing the designated traic direction l.during occupancy of the stretch.l i

Furthermore, as relay Z-ABKSR is certain to 4.5 be released during occupancy of the stretch,` its contact ZI ,is certain to establish the circuit of lamps WFE and EFE so that the appropriate one ,ofv these lamps `is lighted.

If, While the eastbound train under consideration is present in the stretch, the operator Wishes to clear one of the signals 21?. to permit a second or following train to enter the stretch, he may do so .byimoving lever ZSIG to its right-hand position'and pressing the starting button II-ZSTB to pick up relay I-ZST to send acontrol code to the eld station at the left-hand end of the stretch. At this time, the battery is connected to control channel I over lreverse polar contact 3,0 of relay `2--4LP, vfront contact 65 of relay I-2S r land right-hand contact 66 of lever 2SIG so the control ,code transmitted at this time operates the signal control relay to clear one of the signalsZR if trac conditions are proper.

4at ,this time relay 2-4iBKSR is released and Lits contact 50 interrupts the circuit controlled by starting button I-ZSTB so that energy is not suppliedto relay ji-4ST when the starting button jI-ZSTB is depressed. Accordingly', a con.- -trol code is not transmitted to the field station `at the right-hand of the stretch. Since the stretch -is `already prepared for eastbound traino, transmission of a control code to the `east end of the stretch is unnecessary,` and as this system veliminates this control code When it is not required, this system reduces the total number of 11 control codes transmitted and thereby reduces code congestion on the C. T. C. system code line wires.

If, while the stretch is prepared for eastbound trafc, the operator wishes to prepare it for westbound trame, he may do so provided the-stretch is vacant and the signals 2R, are at stop so that the circuits of relay 2-4LP are complete. If lever 4SIG is now moved to its left-hand position and lever ZSIG is in either its center or its lefthand position, energy is supplied over the circuit including back contacts of the various indication relays, contacts 40 and 4l of lever ZWL, contact 68 of lever 4SIG, and Contact 69 of lever ZSIG to the lower winding of relay 2-4LP to move the contacts of relay Z-GLP to their left-hand or normal positions. On this movement of the contacts of relay 2-4LP, the contacts25 and 2E change the polarity of the energy supplied to relay 2-4LPS over its stick circuit and the contacts of relay 2-liLPS release with the result that contacts 23 and 24 of relay 2-4LPS interrupt the relay stick circuit and the relay contacts remain released until the starting relays l-2ST and 3-4ST are picked up to initiate transmission of control codes to both ends of the stretch as explained above. Also on release of relay 2-4LPS pick-up circuits are established for relays ZRBK, ALBK and 2-4BKSR and these relays pick up to light lamp BKE, prevent supply of energy to lamp WFE or and establish the circuits for the starting relays so that both of these relays pick up when either starting button is depressed.

As the contacts of relay 2--4LP are in their left-hand or normal position, energy is supplied over normal contact 30 of relay 2-4LP and front contact E4- of relay l-ZS to channel 2 and the control code sent to the left-hand end of the stretch conditions that end of the stretch to be an exit end. As contact 3!) of relay 2--4LP is in its left-hand position, energy is not supplied to channel 2 on picking up of contact 21 of relay 3,-4S and the control code sent to the right-hand end of the single track stretch conditions that end of the stretch to be the entrance end.

When transmission of control codes to both ends of the stretch is initiated, energy is supplied to relay 2-4LPS over its pick-up circuit and its contacts pick up to interrupt the relay pick-up circuit, establish the relay stick circuit, and interrupt the pick-up circuits of relays 2-4BKSR, ZRBK and 4LBK, while the equipment otherwise operates as explained above during establishment of eastbound trafc.

This system is arranged to insure that even though the contacts of relay 2-4LP are moved more than once before the direction of trafc ls finally determined, the direction of trafc indicated in the oice is the same as that which is established by the Wayside apparatus in the eld.

As pointed out above, when the contacts of relay 2-4LP are moved from one position to the other to change the designated traiiic direction as, for example, from westbound to eastbound, the polarity of the energy supplied to the relay 2-4LPS is changed and its contacts release to pick up relays 2--4BKSR, ZRB-K and 4LBK. If a starting button is now depressed, the relays I-ZST and 3-4ST pick up to cause energy to be supplied to relay 2-4LPS over its pick-up circuit and its contacts pick up to interrupt the relay pick-up circuit and establish the relay stick circuit, while as soon as control codes can be transmitted to the eld stations at the ends of If the operator now decides to restore the origi-A nal direction of traffic, that is, westbound, and moves lever 2SIG to its center or its left-hand position, and moves lever 4SIG to its left-hand position, energy will be supplied to relay 2-4LP to move its contacts to their left-hand position, and on this movement of the relay contacts, the polarity oi the energy supplied to the relay 2-4LPS is changed and the relay contacts release to interrupt the relay stick circuit and establish the pick-up circuits for relays 2-4BKSR, ZRBK and ALBK to pick up these relays if they have released or to maintain them picked up if they have not become released.

If movement of the contacts of relay 2-4LP to their left-hand position occurs prior to transmission of a control code to either end of the stretch, that is, while relays l-ZST and 3-4ST are both picked up, energy will be supplied to relay 2-4LPS over its pick-up circuit as soon as energy is supplied to terminal 5'! of the oice codingunit and the contacts of relay 24LPS will pick up to interrupt the relay pick-up circuit, establish the relay stick circuit, and interruptA the circuits which it controls for relays 24BKSR ZRBK and 4LBK.

If movement of the contacts of relay 2-4LP to their left-hand position occurs prior to transmission of the control codes to either end of the stretch, the control codes which are transmitted will cause the neld station equipment to prepare the stretch for traine in the direction designated by the relay 2-4LP, that is, westbound traflic, and, as relay 2-4LPS is picked up, the indication codes sent to the oice following the control codes will release relays ZRBK, ALBK and 2-4BKSR to show that traffic has been established in the desired direction.

If movement of the contacts of relay 2-4LP to their normal position does not occur until after a control code has been sent to either one or both ends of the stretch, one or both of the starting relays will be released and the pick-up circuit for relay 2-4LPS will not be established and the contacts of relay 2-4LPS remain released after release of the relay following the change in the polarity of the energy supplied to the relay as a result of movement of the contacts of relay 2-4LP.

As it is assumed that one or both of the control codes was transmitted prior to movement of the contacts of relay 2 -4LP to their left-hand or normal position, the equipment at one or both of the field stations will condition the wayside equipment for eastbound traic, while indication codes may thereafter be sent to the oice to release relay ZRBK and/or ihBK, before control codes are transmitted to establish traffic in the direction now designated by relay E4-4LP, that is, westbound'traic. This is particularly true if after returning the contacts of relay 2--4LP to their left-hand positions, the operator delays pressing of a starting button andthus delays transmission of control codes for the new direction of traiiic. v

However, as just explained, relay Z-LILPS is released so that if an indication code is sent to release relay ZRBK or @LBK the relay will release momentarily during the picked-up period of the associated delivery relay D, but Will thereafter be picked up again by energy supplied over 13 the circuit established by a back contact of relay z tL-PS. Accordingly, relays ERBK and ALBK remain picked up and maintain the circuits oi lamp BKH and the stick circuits for relay E-QBKSI-t, with the result that relay fiBKSR is maintained energized by current supplied over bot-h its pick-'up and stick circuits. As

relay `2--5l3iSR is picked up its contacts 29 and "5b maintain the circuits for the starting relays and ii either starting :button is depressed, both starting relays will be picked up so that control codes will be sent to both ends of the stretch to condition the stretch for traiiic in the direction designated by the relay 2-4LP, that is, westbound trafc.

It will be seen `that relay E-dLPS releases Whenever the contacts of relay 2-4LP are moved, and that relay --iLPS when released, remains released until control codes are s ent to both ends of the stretch, while the relay -liLPS when released prevents release of the block indication relays ZRBK and 11113K and of the relay 2--BKSR. This arrangement, therefore, prevents registration of block indication codes unless at the time these codes are received the contacts of relay Z-JZLP are still in the position which :they occupied at the time that the control codes ,producing the indication codes were transmitted. This mode of operation Vprevents indication codes showing that the wayside apparatus is prepared for one direction of trafc being recorded -at a time when the office equipment designates the opposite direction of tra-nic and thereby eliminates any possibility that the directionof traffic reported in the office and that ac' tually established in the field will be out of corresponderme.

Thismode of Voperation also causes the relay E-HBKSR to maintain the circuits for the starting relays to thereby insure that, until trahie is established in `the `designated direction, control codes will be transmitted to both ends of the stretch when the starting button for either end of the stretch is pressed so that the wayside -apparatus will operate promptly and positively to 0 establish :traiiic in the designated direction regardless of Aunusual or irregular manipulation oi the control machine. If the relay Z-BKSR did not operate in this manner to maintain the circuits for the starting relays, under some conditions .pressing of a starting button would energize only the associated starting relay and cause a'control code to be sent only to one end of the stretch with the result .that the wayside yequip-- ment may not prepare the entire stretch for traffic in the desired direction. Although this condition, if lit arises, can readily be corrected by pressing the starting button ifor the station at the other end of the stretch to cause a control code to be transmitted tothat station to thereby cause the wayside equipment to complete preparation of the stretch for traiilc in the desired direction, the operator may not be aware of the cause of the difculty or be familiar with the means for overcoming it, and some delay may be experienced inestablishing trailc in the desired direction. Since this system operates to cause relay :2-1BKSR to maintain the circuits for the starting relays until establishment of traftlc in the designated traffic direction is complete, it i makes operation of the equipment prompt and positive and eliminates delays which might otherwise occur.

This `system is also arranged to contro-1 the wayside'equipment `.togovern electric switch locks on hand-throw switches at intermediate points in a track stretch. As shown in the track diagram at the top of Fig. 1 there is a switch 2W in the single 'track stretch between switches I'W and 3W. rIhis switch is equipped with an electric .lock which is controlled by the wayside signal circuits in the manner explained in detail in the above-identiiied application of H. S. Young. Knowledge of the detailed mode of operation of the wayside signal circuits to control the electric lock for switch 2W is not essential to the underm standing of this invention and it is deemed sufficient to point out that this lock may be energized to permit a train on the siding to enter the main track when and only when energy is'supplied from opposite ends of the stretch to line or other control relays associated with the switch 2W. In order to eiect this simultaneoussupplyoi energy from both ends of the stretch it is necessaryto condition both ends of the stretch to be exit ends and f or the stretch to be unoccupied.

In order to cause the C. T. C. equipment .to transmit control codes whichwill condition both ends of the stretch to be exit ends it is necessary to supply energy to channel 2, or to another channel, such as channel 4, during transmission of control codes to the iield stations at the ends of the stretch.

As shown in Fig. 1, the contacts of 0the `relay 2-4LP are in their left-hand positions to designate west-bound traffic Vfor the stretch, the signal levers ZSIG and SIG are both in their center positions, the sign-als 2R and 4L are at stop so that relays ZRI-IK and LHK are released, and switch lock lever 4WL is in Yits center position. The lever 2WL is preferably of the push-turn `type shown in Letters Patent of the United States No. 2,289,736 `to C. S. Snavely and R. I-I. Zet/Wo.

To enable `a train to enter the main line via switch 2W the central oce operator in response to a'telephone call from the train -crew will move the lever ZV/L to the left or `right according to the direction the train is to move after entering the single track stretch, and if the-entering signals are at stop and the block is unoccupied so that the indication relays are released, movement of the lever 2WL to either of its positions results inthe supply of energy to relay 2-4LP to move its contacts to a position corresponding to that oi lever 2WL if the lever 2WL and the contacts of relay Z-lLP `are out of correspondence.

If lever ZW'L is moved to its `left-hand position, energy is supplied over back contacts of the various indication relays, contacts 40 and 4l of lever 2WL, and contact 69 or lever `ZSIC?, to the lower winding of relay 2-4LP. The energy sup plied to this winding maintains the relay con# tacts in their left-hand position, as shown.

If lever ZWL is moved to its right-hand position, energy is supplied over back contacts oi the various'indication relays, contact 40 of lever ZWL, and contact 43 of lever QSIG to the upper winding of relay 2-4LP to rnove the relay contacts to their right-hand position.

vDuring turning movement of the lever ZWL, contacts 86 and il!) are closed, and when contact 8T of lever 2WL and contact 88 of relay 2--4LP are in correspondence, either as a result of movement of the lever into correspondence with the relay contacts ormovement of the relay contacts into correspondence with the lever, energy is supplied to relays ZRBK and LBK and their contacts .pick up to establish stick circuits for the relays anditocause contacts B6v and .to interrupt the circuits of relay 2-4LP and thus prevent a change in the designated trac direction.

If the contacts of relay 2-4LP are moved as a result of movement of the lever ZWL, the polarity of the energy supplied to the relay 2-4LPS is changed and the relay contacts release. On release of the relay Z-ASLPS at this time, its contact 41 does not establish the pick-up circuit for relay 2-4BKSR since this circuit is interrupted by contact 48 of lever ZWL, Accordingly, relay 2-4BKSR remains released and its contactlllS does not Vestablish the relay stick circuit, while its contact 39 does not establish the connection shunting contacts 35 and 36 of relays lLBK and ZRBK in the circuits of the relay 2-4LP. On release of relay Z-llLPS its contacts 45 and 46 establish pick-up circuits for relays 4LBK and ZRBK to pick up these relays if they are not picked up by energy supplied over other circuits and contacts 35 and 35 of relays 4LBK and ZRBK interrupt the circuits of relay 2-4LP to prevent movement of the relay contacts to change the designated trafc direction.

Momentary closing of front contacts 1) and TI of lever ZWL during turning of lever ZWL establishes pick-up circuits for the relays I-ZST and 3-4ST and initiates transmission of control codes to the eld stations at both ends of the stretch.

On picking up of the starting relays 3--4ST and l-2ST their contacts 52 and 53 permit energy to lbe supplied over the pick-up circuit for relay 2 4 LPS as soon as relays ZRBK and llLBK pick up to close their front contacts 55 and 56 and the olice coding unit operates to supply energy to terminal l'. At this time, as explained above, relay Z-IIBKSR'remains released so its contact 54 in the pick-up circuit for relay 2-4LPS is open, but this Contact is shunted by contact 85 of lever 2WL so energy is supplied to relay 2-4LPS, if the relay contacts released, and the contacts of relay 2-4LPS pick up to establish the stick circuit for relay 2-4LPS and contacts 46 and 45 of relay 2-4LPS interrupt the pick-up circuits for relays ZRBK and 4LBK.

If at the time the control codes are transmitted the lever 2WL and the contacts of relay 2--4LF are both in their left-hand positions, energy is supplied to channel 2 over normal polar contact 3l! of relay 2--4LP and contact 64 of relay l-ZS during transmission of a control code to the west end of the stretch so that the west end of the stretch is made an exit end. In addition, during transmission of a control code to the west end of the stretch, energy is supplied to channel 4 over the circuit including back contact i4 of relay 4LHK, back contact l5 of relay ZRHK, con- .tact 'I6 of lever ZWL, contact 'l1 of lever ZSIG,

contact 'I8 of lever 4SIG, and front contact 80 of relay l-2S so that, as explained in the above identified application of H. S. Young, a relay at the left-hand end of the stretch conditions that end of the stretch to be an exit end if it is not so conditioned by the relay governed over channel 2, while the relay governed over channel 4 prevents transmission of a block clear indication code from the west end of the stretch and the next indication code sent from this field station maintains relay ZRBK picked up so that its contact 36 interrupts the circuits of relay 2-4LP and thus prevents movement of the contacts of this relay to change the designated traflc direction.

When control codes are transmitted to the right-hand end of the stretch and the lever 2WL and the contacts of relay 2-4LP are both in their left-hand positions, energy is supplied to channel 2 over the circuit including back contact 14 of relay ALHK, back contact 75 of relay ZRHK, contact i6 of lever BWL, contact 'Il of lever ZSIG, contact 'i8 of lever ASIG, and front contact 82 of relay 3-4S and this end of the stretch is conditioned to be an exit end. As both ends of the stretch are conditioned to be exit vends the wayside equipment operates to permit the switch 2W to be moved to enable the train on the siding to enter the main track.

If at the time the control codes are transmitted the lever 2WL and the contacts of relay 2-4LP are both in their right-hand positions, energy is not supplied to channel 2 during transmission of a control code to the eld station at the left-hand end of the stretch as normal polar contact 30 of relay 2-4LP is open. However, during transmission of a control code to this eld station, energy is supplied to channel 4 over the circuit including back contact 14 of relay 4LHK, back contact 'l5 of relay ZRHK, contact 16 of lever ZWL, contact TI of lever ZSIG, Contact 'I8 of lever ftsG, and front contact of relay l--ZS so that the relay at the eld station at the left-hand end of the stretch and governed over channel 4 conditions that end of the stretch to be an exit end and also operates to prevent transmission of a block clear indication code from that eld station.

When control codes are transmitted to the eld station at the right-hand end of the stretch and the contacts of relay 2-4LP are in their righthand positions, energy is supplied to channel 2 over reverse polar contact 3B of relay 2-4LP and front contact 21 of relay 3-4S and the equipment at this field station conditions this end of the stretch to be an exit end. As both ends of the stretch are conditioned to be exit ends the Wayside equipment operates to permit the switch 2W to be moved to enable the train on the siding to enter the main track.

After transmission of control codes to the two ends of the stretch an indication code may be sent from the eld station at the right-hand end of the stretch to release relay 4LBK so that its back contact 35 is closed. However, as previously explained, the relay at the eld station at the lefthand end of the stretch and controlled over channel 4 prevents the transmission of a block clear indication code from that station and relay ZRBK is certain to remain picked up so that its contact 36 interrupts the circuits for relay 2-4LP to thereby prevent a change in the position of the contacts of relay 2-4LP. If a change in the position of the contacts of relay 2-4LP could occur following unlocking of the switch 2W and movement of a train over this switch into the main track stretch, it might result in putting to stop in front of the train a signal at an intermediate point in the single track stretch with resultant delay to this train and in clearing of the track stretch for other trac.

This system is arranged to eliminate this possibility by preventing movement of the contacts of relay 2-4LP as the relays ZRBK and 4LBK are picked up as a result of movement of lever 2WL, and the relay ZRBK is thereafter maintained picked up because a block clear indication code cannot be transmitted from the west end of the stretch, while on movement of lever 2WL away from its center position, the relay 2-4BKSR, is maintained released so that its contact 39 does not shunt the contacts of relays ZRBK and 4LBK in the circuits of the relay 2-4LP.

After a train has entered the main track stretch over the switch 2W and the switch has been re-' 17V turned to its original position and locked, the operator may convert the end of the stretch behind the train to an entrance end so that the headblock signal at this location may be cleared to permit a following train to enter the stretch.

If the contacts oi relay 2-4LP are in their lefthand position, as shown, indicating that the train was to gov after entering the main track, the lever 2WL will be in its left-hand position, and on movement of the lever to its center position Contact 'IB of the lever 2WL interrupts the circuits for supplying energy to channel 4 during transmission of a control code to the station at the left-hand end of the stretch, and for supplying energy to channel 2 during transmission of a control code to the station at the right-hand end of the stretch.

On this movement of lever 2WL to its center position, the contacts of relay 2-4LP remain in their lefthand position so there is no change in the energy supplied to `relay 2--4LPS over its stick circuit and the relay contacts remain picked up. Accordingly, when lever 2WL is moved to its center position and its'contaot 48 is closed, energy is not supplied to relay 2-4BKSR as contact 41 of relay 24LPS is picked up. Relay Z-QBKSR, therefore, remains released and its contact 39 does not shunt the contacts of relays ZRBK and LBK in the circuits of relay 2-4LP, and the circuits of relay 2-4LP continue to be controlled by relays ZRBK and 4LBK so that thedesignated direction of traffic cannot be changed at this time.

During movement of the lever 2WL from its left-hand to its center position, contacts 'l0 and 1| momentarily establish circuits for the relays I-ZST and 3-4ST and they pick up to establish stick circuits for themselves and initiate the transmission of control codes to the iield stations. In addition, during movement of lever ZWL to its center position, contacts 86 and 90 establish circuits to supply energy to relays ZRBK and 4LBK and they pick up if they are not already picked up.

If lever llSIG is now moved to its left-hand position, energy will be supplied to channel 5 over normal polar` contact 30 of relay 2-4LP, front contact 3| of relay S-LlS and contact 32 of lever tSIG, during transmission of a control code to the iield station at the right-hand end of the stretch, while energy is not supplied to channel 2 during transmission of a control code to this station so the right-hand end of the stretch is converted to an entrance end and the signal control relay is operated to permit clearing of a signal @L if conditions are proper.

As pointed out above, the circuit for supplying energy to channel 4 during transmission of a control code to the station at the left-hand end of the stretch is interrupted so the equipment at that iield station is converted to a normal exit end and block indication codes may bev transmitted to the oice to show traic conditions in the stretch.

The equipment operates in a similar manner if the train entering the main track over switch 2W had proceeded to the east and the operator had thereafter wished to clear one of the signals 2R behind the train and a detailed explanation of the operation of the equipment at such times is not deemed necessary.

When the lever 2WL is restored to its normal position and control codes `are transmitted while the signal levers are in their stop positions, an end of the stretch is converted from an exit to an entrance end to thereby prepare the stretch for trafElc in the direction designated by relay 2 4LP andthe blockindication relays ERBK and 4LBK thereafter function in the normal manner to prevent energization of relay 2-4LP while the stretch is occupied but to permit this relay to be energized to change the designated traiiic direotionwhen thestretch is vacated.-

Where some `forms of wayside signal circuits are employed, occupancy of an entire stretch is indicated at timesfrom one end of the stretch and at other times from the other end of the stretch instead of a portion of the 'stretch being indicated from one end and the remainder being indicated from the other end. Where this arrangement is employed the block indication re-` lay at :the cnice which is governed from the exit end of the stretch is continuously picked 'up regardless of trafc conditions in the stretch, while the block indication relay at the omce which is governed from the entrance end of the stretch is released or is p-icked up according as the stretch is Vacant or is occupied. Accordingly, where occupancy of the entire stretch is indicated from one end or the other, one or the other of the relays, 4LBK or `ZRBK is released when the i stretch is vacant, but both of these relays are not released at the same time.` In these situations the stick circuit for the relay Z-IlBKSR should be modified as shown in Fig. 2" so that the contacts 6I and'll of these relays'are connected in series instead of in multiple as shown in'Fig. 1. In addition, in these situations, the

shown in Fig. 3 so that contacts 35 andti of relays 4LBK and ZRBK are connected in multiple employ, it is understood that various changes' and modifications may be made therein Within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described o-ur invention, what we` claim is: l i

l."`In direction selecting means for a stretch o railway track equipped with a signaling system governed jointly by code controlled traffic direction relays at opposite ends ofY the stretch so that at times the stretch is conditioned for trafric in one direction andiat other times is conditioned for trafc in the other direction, in combination, `electroresponsive means ata control office including contacts movable between a iirst and a second position for controlling .circuits gov-` erning transmission of control codes to said trafic direction relays to cause them to establish trafic in one direction or the other according as said contacts occupy their iirst ortheir second position, block indication means at said control ofce for indicating whether said stretch is occupied or is unoccupied, circuit means for operating said electro-responsive means to change the position of said contacts provided saidblock indication means indicates 'the stretch to be unoccupied, an auxiliary relay having' contacts movable between a first position in which they permit the block indication means to indicate that Vthe stretch is unoccupied and a second po-l sitionin which they prevent said block indication'` means from indicating that the stretch is unoccupied, means operative `o n movement of,v the contacts of said electroresponsive means. between theirtwo positions to move the contacts of saidV auxiliary relay tol their second position, and means eiective when transmission ofV control codes to the trafllc direction relays at both ends ofthe stretch is initiated for moving. the rcontactsY of said auxiliary Yrelay tol their rst position.

'2.fIn direction seiecting means for a stretch fic in: the directionfdesignated by said electroresponsive means, block indication means at said control oiiice for indicating whether said stretchis occupied or is unoccupied, circuit means foroperating said electroresponsive means to change the designatedftrafiic direction provided said blocl; indication means'v indicates .the stretch to beunoccupied, an auxiliaryrrelay having contacts movable between a Jiirst position in whichl they permit the blockindicationmeans to indi cate that the stretch is unoccupied and a second position in which they prevent said block indication means from. indicating that the stretch is` unoccupied, means responsive to operation of said electroresponsive means to change the designated tralic direction "for moving the ,contacts of said auxiliary relay4 to,` `their second position, and means Yeffective when transmission of control codes to thetraihc'directionrelays v,at'both ends o fcthestretch is `initiated for moving the con-:f tacts of said auxiliary relay to their first posi-A tion. i Y

3. In direction selecting ,means forl Va stretch of railwaytrackequipped ywitl'i a signaling system governed jointly lby code controlled traffic direction relays at opposite endsl of the stretch so that at times4 the stretchis conditioned fior traflic in one direction'and at other "times is vconditionedfor traiiic in theother directiom'in com-v bination, electroresponsive means at v a control oce capable of designating traic in4 one direction or the otherand controlling circuits gov'-vv erning transmission of control codes to said traf c direction relays to' cause them to establish traiiic in' thedirection designated'by said 'electroresponsive means', block indication means at said,V control oflice' for indicating whether said stretch is occupied or is unoccupied, an auxiliary relay having contacts movable between a vfirst position inwhich they permit the block indication means to indicate that the stretch is unoccupied and a second position in which they prevent said block indication means from indicating that the stretchL is unoccupied, a block indication repeater relayh'aving contacts which occupy a 'secondposition when the auxiliary relay contacts are in their second polsition and'whi'ch when in theirsecond vpositionfmove to their rst posi; tion whenfthe block indication means indicates that thepstretchis unoccupied, circuit means for operatings'aid electroresponsive means to 'change 1 the designated traffic direction provided said block indication means indicates that the stretch is unoccupied or the contacts of said Eblock indication repeater relay are in their second position, means responsive to operation of said Aelectroresponsive means to change the designated ing contacts governing transmission of control traffic direction i'or moving the contacts of said auxiliary 'relay to their second position, and means effective whenv transmission or' control codes to the traino direction relays at both ends of thev stretchis initiated for moving the cont-acts of'saidauxilary relay to their rst position.

fi. In direction selecting means for a stretch ofrailway track equipped with a signaling system governed jointly by code controlled traffic direction relays at opposite ends `of the stretch so that at times the stretch is conditioned for traiiic in one direction and at other times is conditioned for traffic in the other direction, in com.- bination, a polarized relay at a control oiice havcodesto said trafc direction relays to cause them tovestablish traine in one direction or the other according as the contacts of said polarized relay occupy (their. normal or their reve-rse position,

' block indication means at said control cnice for indicating whether said stretch is occupied or is unoccupied, circuit means for operating the contactsoil said polarizedV relay between their two p ositions provided said block indication means indicates that the stretch is unoccupied, an auxiliary relay having contacts movable between a iirst position in which they permit the block indication means to indicate that the stretch is unoccupied and a second position in which they prevent said block indication means from indieating: that the stretch is unoccupied, means operative on movement .of the contacts of said polarized relays between their two positions to cause the contacteer said auxiliary relay to occupy their second position, and means effective when transmission of control codes to the traic direction relays at both ends of the stretch is initiated for-causing the contacts of said auxiliary relay to occupy their iirst position.

5. Inl direction selecting means for a stretch of railway track equipped with a .signaling system governedjointly by code controlled traiiic direction relays at opposite ends of the stretch so n that at times 'the stretch is conditioned for trafc in one direction and at other times is condi- Y tioned for tranic in the other direction, in com- (i ii bination, Yelectroresponsive means at a control oiiice capable of designating traffic in one direction or the other and controlling circuits governing transmission of control codes to said tra-ffic direction relays to cause them to establish traffic in the direction designated by said electroresponsive means, circuit means for operating said eiectroresponsive means to change the designated trafc direction, anj auxiliary relay having contacts movable between Aa iirst and a second position, a starting relay for each end of the stretch adapted when actuated to initiate. transmission of a control code to the associated end ofV the stretch, a starting button foreach starting relay, each starting button controlling a circuit for actuating the associated starting relay, means responsive to operation of said electrorev sponsive means to change the designated traiiic direction forcausing thecontacts of said auxiliary. relay to occupy their second position, means effective when the contactsI of said auxiliary relay 2l cuit controlled by the starting button associated with the starting relay forthe other end of the stretch, and means effective when the starting relays for both ends of the` stretch are actuated to cause the contacts of said auxiliary relay to occupy their iirst position.

6. In direction selecting means for a stretch of railway track equipped with a signaling system governed jointly byl code controlled trafc direction relays at opposite ends of the stretch so that at ftimes the stretch is conditioned for traic in one direction and at other times is conditioned for traic in the other direction, in combination, electroresponsive means at a control oice capable of designating traino in one direction or the other and controlling circuits governing transmission of control codes to .said traffic direction relays to cause them to establish trafc in the direction designated by said electroresponsive means, block indication means at said control office for indicating whether said stretch is occupied or is unoccupied, an auxiliary relay having contacts movable between a first position in which they permit the block rindication means to indicate that the stretch is unoccupied and a second position in which they prevent said block indication means from indicating that the stretch is unoccupied, a block indication repeater i relay having contacts which occupy a second position when the auxiliary relay contacts are in their second position and which when in their second position move totheir first position when the block indication means indicates that the stretch is unoccupied, circuit means for operating said electroresponsive means to change the designated traffic direction provided said block indication means indicates that the stretch is unoccupied or the contacts of said block indicationrcpeater relay are -in their second position, a, starting relay for each end of the stretch adapted when actuated to initiate transmission of a control code to the associated end of the stretch, a starting button for each starting relay, each starting button controlling a circuit for actuating the associated starting relay and also controlling a circuit for actuating the starting relay for the other end of the `stretch provided the contacts of said block indication repeater relay are in their second position, means responsive to operation of said electroresponsive means to change the designated traflic direction for causing the contacts` of said auxiliary relay to occupy their second position, and means effective when the starting relays for both ends of the stretch are actuated to cause the contacts of said auxiliary relay to occupy their rst position.

7. In direction selecting means for a stretch of railway track equipped with a signaling system governed jointly by code controlled traffic direction relays at opposite ends of the stretch so that at times the stretch is conditioned for traffic in one direction and at other times is conditioned for traffic in the other direction, in combination, electroresponsive means at a control oice capable of designating traflic in one direction or the other and controlling circuits governing transmission-of control codes to said traffic direction relays to cause them to establish traffic in the direction designated by said electroresponsive means, Circuit means for operating said electroresponsive means to change theV designated traffic direction, a starting relay for each end ofthe stretch adapted when actuated to initiate transmission of a control ,code to the associated end of the stretch, a neutral auxiliary relay having a pick-up circuit established when' the starting relays for -both ends of the stretch are actuated and having a stick circuit including its own front contact, the `pick-up and stick circuits for ,i said auxiliary relay being governed by said electroresponsive means so that the energysupplied to said auxiliary relay over said circuitsdevelops flux of one polarity or the other in the relay core according as the electroresponsive means designates tralc in one Vdirection or the other, and a starting button for each starting relay, each starting button controlling a circuit for actuating the associated starting relay and also controlling a circuit foractuating `the starting relay for the other end of the stretch provided said auxiliary relay is released.

8. In direction selecting means for a stretch of railway track equipped with a signaling systeni governed jointly by code controlled traiiic direction relays at opposite ends of the stretch so'that at times the Stretch is conditioned for traiiicin one direction and at other times is conditioned fortraic in the other direction, in combination, electroresponsive means at a control oihce capable of designatingtraffic in one direction or the other and controlling circuits governing transmission of control codes to said traic direction relaysto cause them to establish traic in the direction designated by said electroresponsive means, circuit means for operating said electroresponsive means to'change the designated trame direction, aneutral auxiliary relay having a pick-up circuit established when` transmission of control codesto both ends of the stretch is initiated and having a stick circuit including its own front contact, the pick-up and stick circuits for said auxiliary relay being governed by said electroresponsive' means so that` the energy supplied to said auxiliary relay over said circuits develops flux of one polarity or the other in the relay according as the electroresponsive means designates traic in one direction or the other, and a, starting button for each end of the stretch, each starting button controlling a circuit for initiating transmission of a control code to the associated end of the track stretch and also controlling a circuit for initiating transmission of a control code tothe other end of the stretch provided said auxiliary relay is released.

9. In direction selecting means for a stretch ofrailway track equipped with a signaling system governed jointly by code'controlled traino direction relays at opposite ends of the stretch so that at times the stretch is conditioned tor traic in one direction and at other times is conditioned for traic in the other direction. in combination.

electroresponsive means at a control oice capable of designating traflic `in one direction or the other and controlling circuits governing transmission of control codes to said traltfic` direction relays to cause them to establish traffic in the direction designated bysaid electroresponsive means, block indication means at said control oice for indicating Whether said stretch is occupied or is unoccupied, a neutral auxiliary relay having contacts effective when picked up to permit the block indication means to indicate that the stretch is unoccupied and effective when released to prevent said block indication means from indicating that the stretch is unoccupied, a

repeaterv relay `having contacts which` occupy a iirst position when the auxiliary relay contacts are released and which when in their first position move to a second position when the block indication means; indicates that the stretch is unoccupied, circuit means for operating said electroresponsive means to change the ydesignated traic direction providedL said block indication means indicates that the stretch is unoccupied or the contacts of said repeater'relay are in their iirstposition, a pick-up circuit for said auxiliary relay established when `transmission of control vcodes to both ends of the stretch is initiated, a stick circuit for said auxiliary relay including its own iront contact, the pick-up and stick circuits for said auxiliary relay being governed by said electroresponsive means so that the energy supplied to said auxiliary relay` develops ilux of one polarity or the other in the'relay according as` said electroresponsive means designates traic in one direction or the other, and a starting button for each endof the stretch, each starting button lcontrolling a circuit for-initiating transmission of a control code to the associated end of the stretch and also controlling a circuit for initiating transmission of a control code to the other end of thestretch provided said repeater relay contacts are in their first position.

10. In direction selecting means for a'stretch of railway track equipped with a signaling system governed jointly by. code controlled-traffic direction relays at opposite ends oithe stretch so that at times the stretch is conditioned for traiiic in one direction and at other .times is f conditioned for trafc in the other direction, in combination, electroresponsive means at a control oiiicecapable of` designating traffic in one direction or the other and controlling circuits governing transmission of controlV codes to said traflic direction relays to cause them to establish traffic in the direction designated by said electroresponsive means, circuit means for operating said electroresponsive means to change the designated'traflic direction, an auxiliary relay assoelated with said electroresponsive means and governed so that its contacts are moved to a first position y'whenever the direction of traflic designated by said electroresponsiveY means is changed, a'starting button for each end of the f` 'i stretch, each starting button controlling acircuit for initiating transmission of a control code to the associated end of the stretch and also controlling a circuit for initiatingtransmission of a control code to the other end of the stretch provided the contacts of said auxiliary relay are in their rst positionjand means effective when transmission of control codes to both ends of the stretch is initiated for moving the` contacts of said auxiliary relay from their rst to 4their second position.

11. In direction selecting means for a stretch of railway track equipped with a signaling system governed ljointly by code controlled trailic direction relays at opposite ends of the stretch so that-at times the stretch is conditioned for traflic in one direction and at other times is conditioned for tralic in the other direction, in combination, electroresponsive means at a control oiiice capable of designating traic in one 4direction or the' other and controlling circuits lgoverning transmissionr of control codes 'to said trafiic direction relays to cause them to establish traffic in the direction designated by said electroresponsive'means, block indication means at said control oiilce ior indicating whether said stretch is occupied or. isunoocupied, an` auxiliary relay associated with said electroresponsive means-and governed so that its contacts are moved toa first position Whenever the direction of traffic Vdesignated by said electroresponsive means is changed, the when in their first position to preventl the'block indication' means from stretch is unoccupied and being movable to a second position in which they permit the *block indication means to indicate that the stretch is unoccupied, circuit means for. operating said electroresponsive means to change the designated traino direction" provided said block indication means indicates lthat' the stretchis unoccupied, a starting' button for each endy of the stretch, each starting button controlling a circuit ior initiating transmission of a control code to the associated end of the stretch and also controlling a circuit fo1` initiating transmission of a control code to the other end of the stretch provided the contacts of said auxiliary relay are in their rst position,` and means effective when transmission l of control codes to both ends of the-stretch is initiated for moving the contactsv of said auxiliary relay second position.

l2. In direction selecting means fora stretch of railway track equipped with a signalingsystem including entering signals at opposite ends of the stretcnwhich are governed by code controlled relays so that at times thesignal at one end of the stretch may be cleared and Yat other times the signal at the other end of the'stretch maybe cleared, in combination, electroresponsive means at a controloiiice capablefof'designating tralriic in one direction Vor the other and controlling circuits governing transmission 0f control codes to said signal control relays to cause them t'o permit clearing of the signal governing traic in the diiectiondesignated by said electroresponsive'means, an auxiliary relay associated with said-electroresponsive means and governed so that its contactsrare moved toa rst position whenever the `direction oitraiiic designated by said electroresponsive means is changed, a startfrom their rst to their ing button for each end of the stretch,` each start' ing button controllingra circuit for initiating transmission of a-control code to the associated end of the stretch and also controlling a circuit for initiating transmission of a control code `to the other end `of the stretch provided the conA tacts oi' said auxiliary relay' are in their first position, and means effective lwhen transmission of control codes to both ends of the stretch is initiated for moving the contacts of said auxiliary relay from their rst to their second position.

i3.Av In direction selecting means for a stretch of railway track equipped with a signalling system governed jointly by code controlled relays at opposite ends of the stretch, the equipment at each end of thefstretch being capable of conditioning the associated end of the stretch to be an exit or an entranceA end, in combination, electroresponsiveameans at a control oiiice capable of designating traffic in one direction or the other and controlling circuits governing transmission of control codes to said code `controlled relays to cause them to establish traffic inthe direction designated by said electroresponsive means, block indication means at said control oiiice for indi-y cating whether said stretch lis occupied or is unoccupied, an auxiliary relay having contacts movable between a first position in Which'they permit the block indication means to indicate that the stretch is unoccupied and a second position in which they prevent said block indication l'means from Aindicatingr thatV the `stretch is unoccupied, means 'for' governing said` auxiliary relay' t'o cause auxiliary relay contacts being effective indicating that thev I its contacts to moveto their second position whenever the direction of traii'ic designated by said electroresponsive means is changed, a switch lock control member having a normal position from which it is movable to an unlocked position in which it controls the circuits governing transmission of control codes to said code controlled relays to cause the relays at both ends of the stretch to condition the associated end of the stretch to be an exit-end, a repeater relay having contacts which are moved to a second position when the auxiliary relay contacts are in their second position provided said switch lock member is in its normal position and which when in their second position move to their iirst position when i the block indication means indicates that the stretch is unoccupied, circuit means for operating said electroresponsive means to change the designated traiiic direction provided said block indication means indicates that the stretch is unoccupied or the contacts of said repeater relay are in their second position, and means effective when transmission of control codes to both ends of the Stretch is initiated for moving the contacts of said auxiliary relay to their iirst position.

14. In direction selecting means for a stretch of railway track equipped with a signaling system governed jointly by code controlled relays at opposite ends of the stretch, the equipment at each end of the stretch being capable of conditioning the associated end of the stretch to be an exit or an entrance end, in combination, electroresponsive means at a control oiiic capable of designating traic in one direction or the other and controlling circuits governing transmission of control codes to said code controlled relays to cause them to establish traic in the direction designated by said electroresponsive means, block indication means at said control oflice for indi-- eating whether said stretch is occupied or is unoccupied, an auxiliary relay having contacts movable between a rst position in which they permit the block indication means to indicate that the stretch is unoccupied and a second position in which they prevent said block indication means from indicating that the stretch is unoccupied, means for governing said auxiliary relay to cause its contacts to move to their second position whenn ever the direction of trailic designated by said electroresponsive means is changed, a switch lock control member having a normal position from which it is movable in either direction to positions in Which it controls the circuits governing transmission of control codes to said code controlled relays to cause the relays at both ends of the stretch to condition the associated end of the stretch to be an exit end and in which if said block indication means indicates that the stretch is unoccupied said member governs circuit means to cause said electroresponsive means to designate traffic in the direction determined by the direction in which said switch lock control memn ber is moved from its normal position, a repeater relay having contacts which are moved to a sec ond position when the auxiliary relay contacts are in their second position provided said switch lock member is in its normal position and which when in their second position move to their iirst position when the block indication means indicates that the stretch is unoccupied, other circuit means for operating said electroresponsive means to change the designated traflic direction provided said block indication means indicates that the stretch is unoccupied or the contacts of said repeater relay are in their second position, and

`means effective when transmission `of control codes to lbothends of the stretch is initiated for moving the contacts oi said auxiliary relay to their rst position.

15. In direction selection means for a stretch or railroad track having at one end a first detector section and having at the other end a sec` ond detector section, said track stretch being equipped with signalling apparatus governed jointly 'by code controlled traffic direction relays at opposite ends of thestretch so that at times the stretch is conditioned for traffic in one direction and at other times is conditioned for traiilc in the other direction, in combination, electroresponsive means at a control oice capable of designating traic in one direction or the other and controlling circuits governing transmission of control codes to said trailic direction relays to cause them to establish tramo in the direction designated by said electroresponsive means, block indication means at said control oilice for indicating occupancy of said stretch, detector section indication means at said control office for each of said detector sections for indicating occupancy thereof, a block indication repeater relay having contacts which are moved from a first to a second position on operation of said electroresponsive means to change the designated trafc direction and which are moved from their second to their rst position when said block indication means indicates that said stretch is unoccupied or said detector section indication means indicates that a detector section is occupied, and circuit means for operating said electroresponsive means to change the designated trailc direction provided said block indication means indicates that the stretch is unoccupied or the contacts of said repeater relay are in their second position.

16. In direction selection means for a stretch of railroad track having at one end a rst detector section and having at the other end a second detector section, said track stretch being equipped with signaling apparatus governed jointly by code controlled tramo direction relays at opposite ends of the stretch so that at times the stretch is conditioned for traii'ic in one direction and at other times is conditioned for traffic in the other direction, in combination, electroresponsive means at a control office capable of designating traffic in one direction or the other and controlling circuits governing transmission of control codes to said traic direction relays to cause them to establish traic in the direction designated by said electroresponsive means, block indication means at said control ofce for indicating occupancy of said stretch, detector section indicationsv means at said control office for each of said detector sections for indicating occupancy thereof, a block indication repeater relay having contacts which are moved from a rst to a second position on operation of said electroresponsive means to change the designated traic direction and Which are moved from their second to their rst position when said block indication means indicates that said stretch is unoccupied or said detector section indication means indicates that a detector section is occupied, and circuit means for operating said electroresponsive means to change the designated traffic direction provided the detector section indication means shows the detector sections to be unoccupied and also provided said block indication means indicates that the block is unoccupied or the contacts of said repeater relay are in their second position.

17. Direction selecting apparatus for controllingvtrafric movements over a stretch of single track railway equipped with a reversible signaling system, said track stretch having at one end a rst detector section and having at the other end'a second detector section, electroresponsive means at a control o'ice capable of designating traiiic in one direction or the other, a code coinmunication` system for transmitting manually initiated control codes reflecting the conditionof said electroresponsive means to stations at the ends of said stretch to control said signaling systern and for automatically transmitting indication codes from said stations reflecting the condition of occupancy of the stretch to control block indication relays at the office and reflecting the condition of occupancy of said detector sections to control detector section indication relays at the oice, a repeater relay at said control oflice, means effective when said electroresponsive means is operated to change the designated trafc 28 direction for moving the contacts of said repeater relay from their first to their second position and for operating said block indication relays to the positions which they assume in response to received codes indicating that the stretch is occupied, means for moving the contacts of said repeater relay from their second to their first position when indication codes are received to operate the block indication relays to the positions which they assume when the stretch is unoccupied or when an indication code is received that one of said detector sections is occupied, and circuit means for operating said electroresponsive means to change the designated direction of traiic provided said block indication relays are in the position which theyassume in response to received codes indicating that the stretch is unoccupied or the contacts of said repeaterrelay are in their second position.

FRANK T. PASCOE.

ARTHUR L. JEROME. 

